1. Field of the Invention
This invention relates to a vehicular armrest, and more particularly, to an armrest having a structural substrate, a vinyl or flexible polyolefin covering and a foam filling between the substrate, secondary substrate and cover and the vinyl covering. The invention also relates to a process for fabricating the vehicular armrest.
2. Related Art
Armrests filled with polyurethane foam resins have been mounted on vehicle doors for many years. An example of a prior art armrest 110 is shown in FIG. 1 comprising a structural plastic or metal internal support 112 having a substrate surface 120, a vinyl or flexible polyolefin outer cover 118 and a polyurethane or similar foam filling 146 enclosed within the internal support 112 and cover 118 by a panel 114.
While such conventional foam materials have been readily utilized in the industry, problems have been identified with respect to, among other things, the consistency of their reaction profiles. For example, armrests 110 are conventionally filled with a two-part polyurethane foam. Polyurethanes are generically prepared by nucleophilic addition of alcohols to isocyanates. Foaming occurs when a small amount of water is added to the two chemical reagents during polymerization. Specifically, water adds to the isocyanate groups providing carbamic acids, which spontaneously lose carbon dioxide, thus generating bubbles and, in turn, foam within the curing polymer.
When the polyurethane foam 146 is poured into the armrest 110 during the initial stages of polymerization the reagents are still susceptible to parameter changes such as atmospheric moisture (humidity), temperature, and pressure changes. These parameter changes can have a substantially adverse impact upon the consistency of the resulting foam 146 from day to day or even batch to batch. Furthermore, according to conventional methods, after the two-part polyurethane foam 146 has been poured and cured, copious quantities of scrap remain, which requires additional time and labor to clean up and, in turn, adds to the cost of production. Moreover, the disposal of the scraps and byproducts from synthesizing polyurethanes can be costly.
In addition, due to the complexity, smell, and messiness of preparing polyurethane foams, it is typically not practical for the armrest 110 to be assembled in one location as the preparation of the foam 146 requires an additional, separate work station which further adds to the cost of manufacturing. Further, the polyurethane foams 146 are not recyclable and thus the armrests 110 are not recyclable when the automobile is eventually scrapped.